[8.06] The solar phase curve for the bright Plutino 2000 EB173

D. Rabinowitz (Yale University), B. Schaefer (U. Texas, Austin)

Here we report measurements of the phase curve for 2000
EB173, a bright Plutino with opposition magnitude R=19.1 and
red color V-R=0.57+/-0.05 discovered by the QUEST survey[1].
We made all observations from November 2000 to May 2001 with
1.0-meter Yale Telescope at Cerro Tololo, Chile using
Johnson V and R filters and CCD. Exposures times were short
(<5 minutes) to allow small-aperture photometry,
calibrated with secondary standards in each field which we
observed on photometric nights. The phase curve, measured
from phases of 0.28 to 1.9 degrees, is linear with a slope
of 0.165 mag/deg. Assuming a curve of the form defined by
Bowell et al. [2], a minimal chi-squared fit to our R
observations yields H=4.99+/-0.01, G=0.16+/-0.06 (assuming
V-R=0.57). We see no evidence for rotational modulation
greater than 0.05 magnitudes, and the V-R color we measure
at phase angle 1.8 degrees is consistent with earlier
measurements. The phase curve is unusually steep compared to
other icy bodies observed in the outer solar system [3].